a) Field of the Invention
The present invention is directed to an arrangement and a method for eye examination and for determining eye data through measurement technique in which the movement of the eyes is compensated through the use of an eye tracker unit so that results are achieved faster and with increased measuring accuracy.
b) Description of the Related Art
There are numerous ophthalmologic devices known from the prior art that can be used to enable determined measurement tasks on the eye and to find and examine points or regions in the eye.
Patent EP 1 088 511, for example, describes an ophthalmologic device which has a positioning unit for orientation of the measuring unit with respect to the eye to be examined. For this purpose, a detection unit which determines the relative position of the measurement unit with respect to the eye and monitors this position during measurement is provided. The determined measurement values are stored or rejected depending on the eye position determined by the detection unit. In this way, only measurements that were recorded when the eye was accurately positioned are processed and stored. This solution is disadvantageous due to the fact that the measurement unit of the ophthalmologic device must be roughly oriented by the user by means of a joystick at the start of the examination.
An automatically aligning optometric measurement device and the method for its use are described in U.S. Pat. No. 6,145,990. This solution has means for projecting a light mark on the eye, means for evaluating corneal reflex images, and means for controlling the actuating drives for exact positioning of the optometric measurement device. Positioning is carried out in all three coordinate directions for the first eye and then for the second eye based on the position of two light marks relative to one another, these light marks being generated from the corneal reflex image.
In the solution described in U.S. Pat. No. 6,220,706, the position of the eyes is likewise determined by illuminating the eyes and subsequently evaluating the reflected beam. For this purpose, two pairs of radiation emitters and photodetectors are arranged in such a way that the photodetectors can receive the radiation that is emitted by the respective associated radiation emitter and reflected by the eye. A controller analyzes the data of the photodetectors, which are constructed as 4-quadrant photodetectors, in order to determine the exact position of the eye. This technical solution determines, in particular, the focus position, i.e., the exact distance of the corneal vertex from the optics of the device.
While the known technical solutions are capable of aligning to the eye of the patient, finding determined points or regions still depends upon the skill of the operator. The duration of an examination, e.g., for monitoring the healing process after a surgical procedure, depends upon how quickly the operator finds the determined point or region in question. Further, it is not possible to carry out an examination under consistent conditions, so that the healing process likewise depends upon the subjective assessment of the operator.